Page 404 - Review of Medical Microbiology and Immunology ( PDFDrive )

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CHAPTER 46 Minor Viral Pathogens
globulin containing antibody to herpes B virus should be
The rare cases seen in the United States have occurred in
given after a monkey bite.
travelers returning from that continent. American military
personnel in Asia have been affected.
HUMAN BOCAVIRUS
Japanese encephalitis virus is a member of the flavivirus
Human bocavirus (HBoV) is a parvovirus isolated from
Culex mosquitoes endemic to Asian rice fields. There are
young children with respiratory tract infections. Antibody
two main reservoir hosts—birds and pigs. The diagnosis
to HBoV is found in most adults worldwide. A description
can be made by isolating the virus, by detecting IgM anti-
of this virus was first reported in 2005, and its precise role family. It is transmitted to humans by certain species of
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body in serum or spinal fluid, or by staining brain tissue
in respiratory tract disease has yet to be defined.
with fluorescent antibody. There is no antiviral therapy.
Prevention consists of an inactivated vaccine and pesticides
HUMAN HERPESVIRUS 6
mended for individuals living in areas of endemic infection
This herpesvirus is the cause of exanthem subitum (rose-
for several months or longer.
ola infantum), a common disease in infants that is charac-
terized by a high fever and a transient macular or
maculopapular rash. The virus is found worldwide, and up
LASSA FEVER VIRUS
to 80% of people are seropositive. The virus is lympho-
tropic and infects both T and B cells. It remains latent
of that name. It causes a severe, hemorrhagic fever charac-
within these cells but can be reactivated in immunocom-
terized by multiorgan involvement. The disease begins
promised patients and cause pneumonia. Many virologic
slowly with fever, headache, vomiting, and diarrhea and
and clinical features of human herpesvirus 6 are similar to Lassa fever virus was first seen in 1969 in the Nigerian town
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progresses to involve the lungs, heart, kidneys, and brain. A
those of cytomegalovirus, another member of the herpes-
petechial rash and gastrointestinal tract hemorrhage ensue,
virus family.
followed by death from vascular collapse. The fatality rate
HUMAN METAPNEUMOVIRUS
Lassa fever virus is a member of the arenavirus family,
which includes other infrequent human pathogens such as
This paramyxovirus was first reported in 2001 as a cause
lymphocytic choriomeningitis virus and certain members
of severe bronchiolitis and pneumonia in young children
of the Tacaribe group. Arenaviruses (“arena” means sand)
in the Netherlands. It is similar to respiratory syncytial
are united by their unusual appearance in the electron
virus (also a paramyxovirus) in the range of respiratory
microscope. Their most striking feature is the “sandlike”
tract disease it causes. Serologic studies showed that most
children have been infected by 5 years of age and that this
tion, if any, of these ribosomes is unknown. Arenaviruses
virus has been present in the human population for at least
are enveloped viruses with surface spikes, a helical nucleo-
50 years. particles on their surface, which are ribosomes. The func-
capsid, and single-stranded RNA with negative polarity.
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The natural host for Lassa fever virus is the small rodent
Mastomys, which undergoes a chronic, lifelong infection.
JAMESTOWN CANYON VIRUS
Jamestown Canyon virus (JCV) is a member of the bunya-
food or water with animal urine. Secondary transmission
virus family that causes encephalitis. It is transmitted by
among hospital personnel occurs also. Asymptomatic
mosquito bite, most commonly by Aedes species. JCV cir-
infection is widespread in areas of endemic infection.
culates widely among deer in North America but human
The diagnosis is made either by isolating the virus or by
disease is rare. In the United States, cases are primarily in
detecting a rise in antibody titer. Ribavirin reduces the
the northeastern and midwestern states. There is no antivi-
mortality rate if given early, and hyperimmune serum,
ral treatment or vaccine for JCV infections.
ease, has been beneficial in some cases. No vaccine is avail-
able, and prevention centers on proper infection control
JAPANESE ENCEPHALITIS VIRUS obtained from persons who have recovered from the dis-
practices and rodent control.
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This virus is the most common cause of epidemic enceph-
alitis in rural areas of Asia. The disease is characterized by
LUJO VIRUS
fever, headache, nuchal rigidity, altered states of conscious-
ness, tremors, incoordination, and convulsions. The mor-
similar to Lassa fever. This virus emerged in Zambia in
tality rate is high, and neurologic sequelae are severe and
2008 and caused an outbreak in which four of the five
can be detected in most survivors. The disease occurs
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